Q: Vesicoureteral reflux (VUR), also known as vesicoureteric reflux, is a condition in which urine flows retrograde, or backward, from the bladder into the ureters / kidneys. Urine normally travels in one direction (forward, or anterograde) from the kidneys to the bladder via the ureters, with a 1-way valve at the vesicoureteral (ureteral-bladder) junction preventing backflow. The valve is formed by oblique tunneling of the distal ureter through the wall of the bladder, creating a short length of ureter (1 -- 2 cm) that can be compressed as the bladder fills. Reflux occurs if the ureter enters the bladder without sufficient tunneling, i.e., too "end-on".

Answer this question: which disorder involves the retrograde passage of infected urine?
A: Vesicoureteral reflux ( VUR ) , also known as vesicoureteric reflux
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Explanation: To answer the above question, the relevant sentence is: Vesicoureteral reflux (VUR), also known as vesicoureteric reflux, is a condition in which urine flows retrograde, or backward, from the bladder into the ureters / kidneys.